Fenders are used to prevent damage to boats, vessels and berthing structures. To do this, fenders usually have high energy absorption and low reaction force. In berthing a fender is used to absorb the kinetic energy of a boat or vessel berthing against a jetty, quay wall or other vessel. The fender system of the present invention is to be placed at a quay and is mainly intended for harbours receiving relatively large ships or vessels.
To protect both the vessels and the quay, fenders are placed at the quay wall. The fenders are facing out of the quay wall and are to absorb the impact of a berthing vessel. For large vessels fender systems are normally used, wherein one or more fenders carry some kind of shield. One or more shields are to abut the side of the ship and at least parts to be facing a vessel are made of a material that will not damage the side of the berthing vessel. The shields should have relatively low surface friction. The fenders used are normally made in one piece and may be relatively heavy and cumbersome to handle.
Depending on the size of the vessel the impact to be absorbed will vary. If vessels of a larger size than vessels previously received at a specific quay are to be received, it may be necessary to replace the existing fenders. The fenders may also need to be replaced depending on the type of vessel to be received at the quay. For example cruising ships may need another type of shock absorbing than a cargo ship. During the time the fenders are replaced said quay or part of a quay cannot be used. Replacement of broken fenders may also be needed from time to time. Time at which a quay cannot be used means that cargo cannot be loaded or unloaded from vessels, which can be very costly.
From a port engineering perspective there are some problems with fender assembly for the fender systems used today. The fenders are made in one piece and both the shield and the fenders are relatively heavy, making it cumbersome to handle such a fender system, both at mounting and transporting. The fenders have normally an inner void, which is open at the ends of the fender. This may lead to build up of pressure inside the fender at berthing, due to possible assembly of water and ice inside the fender. Such build up of pressure may lead to damages both to the fender system and the vessel. If water or ice is assembled inside a fender the absorbing characteristics of the fender will be affected in that it will make the fender stiffer.